Time-dependent fatigue reliability analysis method based on bilinear cumulative damage

Abstract

The invention discloses a time-dependent fatigue reliability analysis method based on bilinear cumulative damage. The method includes the steps that 1, the probability distribution type and statistical characteristic parameter of fatigue life data are determined; 2, the appropriate reference life is selected, and a bilinear cumulative damage physical model is built; 3, according to the bilinear cumulative damage physical model, a probability cumulative damage model is built; 4, according to the stress-strength interference theory, a time-dependent fatigue reliability model is built; 5, a reliability curve is drawn and compared with an experimental result; the characteristics of a crack initiation stage and a crack propagation stage in the fatigue failure process and the randomness in the damage accumulation process are comprehensively considered, the bilinear damage theory serves as a modeling base, the probability cumulative damage model is built, through the combination with the stress-strength interference theory, the time-dependent fatigue reliability model based on cumulative damage and critical damage is built, the time-varying characteristics of fatigue loading and the dynamic behavior of the damage accumulation process are reflected, and the reliability prediction in the whole fatigue life cycle is achieved.

Description

technical field [0001] The invention belongs to the technical field of fatigue reliability analysis and fatigue life evaluation, and in particular relates to a reliability analysis method of fatigue failure. Background technique [0002] Fatigue damage has become one of the main failure modes of most mechanical equipment structures. According to statistics, the fracture damage caused by fatigue of mechanical components has reached 50% to 90%. Fatigue phenomena have spread across many fields such as aerospace, rail transit, shipbuilding, bridge construction, and machinery manufacturing, and fatigue accidents caused by them have emerged in endlessly. Fatigue damage is highly concealed and sudden, and there is no obvious sign before the damage, which poses a serious threat to the safe operation of mechanical equipment. Once damage occurs, it is easy to cause major accidents and loss of life and property. The fatigue life and reliability of mechanical equipment components or s...

AI Technical Summary

Problems solved by technology

Among them, the linear damage rule or Miner's rule has been widely used in structural fatigue analysis due to its simple form, but this rule has the following two defects: ① It simplifies the fatigue failure mechanism and does not consider the sequence effect of load loading; ② It is a deterministic cumulative damage theory and cannot reflect the dispersion and uncertainty of cumulative damage

However, most of these modeling methods are still based on Miner's law, which cannot reveal the physical nature of the failure process.

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